President Trump said lots of good and important things in Riyadh on Sunday — but count us doubtful that his hosts will act on perhaps the most important: “Young Muslim boys and girls should be able to grow up free from fear, safe from violence and innocent of hatred.”

Innocent of hatred? The Saudis fund hate-driven preaching all across the globe.

The theologians of al Qaeda and ISIS take this hatred a step or two past where the Saudi Salafists (or, as mostly non-Muslim critics term them, Wahhabis) go, but the chief difference is that the “philosophers” of terror don’t balk at criticizing the Saudi government — that is, the royal family.

But the sermons still rail against the infidels, especially the Jews.

And the Saudi export of hate radicalized the Muslim world long before the rise of al Qaeda; indeed it is what made it possible.

The president rightly noted, “A better future is only possible if your nations drive out the terrorists and drive out the extremists.” In the nearly 16 years since 9/11, the Saudi state has driven out some terrorists, but never stopped encouraging extremists.

Trump spelled it out: Change “means standing together against the murder of innocent Muslims, the oppression of women, the persecution of Jews, and the slaughter of Christians. Religious leaders must make this absolutely clear — barbarism will deliver you no glory. Piety to evil will bring you no dignity.”

Until the House of Saud commits to that message, it remains a huge part of the problem.